A microwave tube was charged with 2-(1,3-dioxoisoindolin-2-yloxy)acetamide (intermediate V) (166 mg, 0.76 mmol), hydrazine monohydrate (34.4 mg, 0.69 mmol) and 2 mL of methanol. It was heated at 95° C. for 12 h under microwave irradiation. After cooling, solid was removed by filtration and the solution was concentrated under reduced pressure. The residue was diluted with methanol, then 1-(3-(quinolin-6-ylmethyl)-[1,2,4]triazolo[4,3-b]pyridazin-6-yl)ethanone (41.2) (32 mg, 0.105 mmol) and 0.3 mL of acetic acid were added and the mixture was stirred at 40° C. overnight. After concentration, the residue was purified by prep-HPLC to afford the title compound. 1H-NMR (400 MHz, DMSO-d6) δ ppm 8.86 (dd, 1H), 8.33-8.27 (m, 2H), 7.98-7.95 (m, 2H), 7.78 (dd, 1H), 7.69 (d, 1H), 7.50 (dd, 1H), 7.31 (d, 2H), 4.77 (s, 2H), 4.63 (s, 2H), 2.32 (s, 3H). LCMS (method A): [MH]+=376, tR=4.02 min.
